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Publications


2008

MR. ODONGO, HESBONO.  2008.  Khat (Catha edulis) lowers plasma luteinizing hormone (LH) and testosterone secretion, but increases cortisol levels in male rabbits.. Journal of the South African Veterinary Association. 73, 201-206. : Journal of ethnopharmacology;116(2):245-50 Abstract
This study investigated the effects of fresh khat extract on specific circulating hormones in male rabbits. MATERIALS AND METHODS: A total of 25 male New Zealand White rabbits were divided into five groups each comprising five animals. The first four groups were fed four doses (1.5 g/kg, 4.5 g/kg, 13.5 g/kg and 40.5 g/kg body weight) of khat extract twice a week for 5 weeks while the last group, serving as control, was fed only normal saline via intragastric tube. Blood samples were collected at 15 min interval for up to 3 h after khat extract administration and plasma assayed for luteinizing hormone (LH), testosterone and cortisol levels using radioimmunoassay technique. RESULTS: Khat extract at all doses significantly lowered (P<0.05) LH pulse frequency, area under LH curve, mean plasma LH and mean plasma testosterone levels. Plasma cortisol levels were significantly elevated (P<0.05) in khat-treated rabbits in a dose-dependent manner. CONCLUSION: This study demonstrates that khat may impair reproductive function in male rabbits by interfering with sex hormone profiles.

2007

MR. ODONGO, HESBONO.  2007.  In vitro study of the effects of khat (Catha edulis Forsk) extract on isolated mouse interstitial cells.. Journal of the South African Veterinary Association. 73, 201-206. : Journal of ethnopharmacology;110(3):401-5. Abstract
Isolated mouse interstitial cells were incubated with different concentrations of khat (Catha edulis) extract (0.06 mg/ml, 0.6 mg/ml, 6 mg/ml, 30 mg/ml and 60 mg/ml) and cell viability as well as testosterone concentration measured at 30 min intervals over a 3h incubation period. High concentrations of khat extract (30 mg/ml and 60 mg/ml) significantly inhibited testosterone production while low concentrations (0.06 mg/ml, 0.6 mg/ml and 6 mg/ml) significantly stimulated (P<0.05) testosterone production by mouse interstitial cells. Similarly, at concentrations of 30 mg/ml and 60 mg/ml, there was a significant decrease in interstitial cell viability, whereas at 0.06 mg/ml, 0.6 mg/ml and 6 mg/ml there was no significant decrease. There was only a weak correlation (r=0.39) between testosterone production and viable interstitial cells. We postulate that khat extract at high concentrations may cause reproductive function impairment in the user but at low concentrations, may enhance testosterone production with accompanying effects on reproductive functions in male mice.

2006

MR. ODONGO, HESBONO.  2006.  The pesticide heptachlor affects steroid hormone secretion in isolated follicular and luteal cells of ratJ. A. Odumaa, Corresponding Author Contact Information, E-mail The Corresponding Author, D. Oduor Okeloa, H. Odongoa, D.W. Makawitib Purchase a Reprod. Journal of the South African Veterinary Association. 73, 201-206. : Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology Vol 144, Issue 1,
MR. ODONGO, HESBONO.  2006.  The pesticide heptachlor affects steroid hormone secretion in isolated follicular and luteal cells of rat.. Journal of the South African Veterinary Association. 73, 201-206. : Comparative biochemistry and physiology. Toxicology & pharmacology : CBP;144(1):76-84. Abstract
Heptachlor, a chlorinated hydrocarbon pesticide, suppresses the production of progesterone and estradiol in the female rat in vivo or in isolated ovaries in vitro. In this study the effect of heptachlor on steroid hormone production by isolated rat luteal and follicular cells, in the presence of two precursor hormones was investigated. Ovaries were isolated from anesthetized mature normocyclic virgin rats (3 to 4 months old), under sterile conditions. Corpora lutea and follicles were microscopically dissected out and separately enzymatically dispersed with collagenase at 37 degrees C. Viable cells collected after centrifugation were used at a concentration of approximately 2.5 x 10(5) cells/10 mL. Both luteal and follicular cell preparations were separately incubated overnight (15 h) at 37 degrees C in the presence of pregnenolone (P5) and androstenedione (A4) at a concentration of 6.0 nmol/L each, and heptachlor at either 0.12 microg/mL (low dose) or 1.20 microg/mL (high dose) (test cells) or in the absence of heptachlor (control cells). At the end of the incubations, progesterone and estradiol 17beta levels were analyzed in the incubation media. The results indicate that heptachlor significantly suppressed the production of both progesterone and estradiol in both cell types in a dose related manner even in the presence of A4 and P5 as precursor hormones (P<0.05).
MR. ODONGO, HESBONO.  2006.  The pesticide heptachlor affects steroid hormone secretion in isolated follicular and luteal cells of rat.. Journal of the South African Veterinary Association. 73, 201-206. : Comparative biochemistry and physiology. Toxicology & pharmacology : CBP;144(1):76-84. Abstract
Heptachlor, a chlorinated hydrocarbon pesticide, suppresses the production of progesterone and estradiol in the female rat in vivo or in isolated ovaries in vitro. In this study the effect of heptachlor on steroid hormone production by isolated rat luteal and follicular cells, in the presence of two precursor hormones was investigated. Ovaries were isolated from anesthetized mature normocyclic virgin rats (3 to 4 months old), under sterile conditions. Corpora lutea and follicles were microscopically dissected out and separately enzymatically dispersed with collagenase at 37 degrees C. Viable cells collected after centrifugation were used at a concentration of approximately 2.5 x 10(5) cells/10 mL. Both luteal and follicular cell preparations were separately incubated overnight (15 h) at 37 degrees C in the presence of pregnenolone (P5) and androstenedione (A4) at a concentration of 6.0 nmol/L each, and heptachlor at either 0.12 microg/mL (low dose) or 1.20 microg/mL (high dose) (test cells) or in the absence of heptachlor (control cells). At the end of the incubations, progesterone and estradiol 17beta levels were analyzed in the incubation media. The results indicate that heptachlor significantly suppressed the production of both progesterone and estradiol in both cell types in a dose related manner even in the presence of A4 and P5 as precursor hormones (P<0.05).

2004

MR. ODONGO, HESBONO.  2004.  PHYSIOLOGIC MANIFESTATIONS OF STRESS FROM CAPTURE AND RESTRAINT OF FREE-RANGING MALE AFRICAN GREEN MONKEYS (CERCOPITHECUS AETHIOPS). Journal of the South African Veterinary Association. 73, 201-206. : journal of Zoo and wild life medicine35(1) Abstract
Adrenal gland weights, stomach mucosal lesions, and morning serum cortisol and prolactin levels were measured in 15 juvenile and adult male African green monkeys (Cercopithecus aethiops) that were shot by a hunter, euthanized after 24 hr of captivity, or euthanized after 45 days of captivity and intermittent blood sampling. Hormone levels were measured in seven additional males that had been in captivity for 7 mo. Mean serum cortisol concentrations were significantly lower in free-ranging wild monkeys at the time they were shot than in the monkeys after 1 day in captivity. Cortisol concentrations were significantly higher in wild-caught monkeys on the day after capture than they were in the same animals after 18 and 26 days of captivity. Cortisol concentrations were also significantly higher in the wild-caught monkeys 18 days after capture than in the laboratory-habituated monkeys in captivity for 7 mo. Mean prolactin concentration was significantly lower in the wild-caught monkeys on day 2 after capture, and the levels increased gradually to 45 days in captivity and was highest in monkeys that had been captive for 7 mo.

1997

MR. ODONGO, HESBONO.  1997.  In vitro production of testosterone and plasma levels of luteinising hormone, testosterone and cortisol in male rats treated with heptachlor. E O Wango, D W Onyango, H Odongo, E Okindo, J Mugweru. Journal of the South African Veterinary Association. 73, 201-206. : Comparative biochemistry and physiology. Part C, Pharmacology, toxicology&endocrinology.118(3):381-6 Abstract
Male rats were divided into six groups of five rats each. Rats were injected subcutaneously with different concentrations of heptachlor for 2 weeks. Heptachlor at all doses significantly suppressed plasma testosterone levels (P < 0.05). Plasma luteinizing hormone (LH) (P < 0.01) and cortisol (P < 0.02) levels were significantly elevated in heptachlor-treated rats as compared to corn oil-treated controls. LH and testosterone levels showed strong correlation (r = 0.69, P < 0.05). The testes in rats treated with 25 mg/kg body weight of heptachlor showed some pathological changes. We conclude that heptachlor causes adverse effects on several male reproductive parameters in rats.
MR. ODONGO, HESBONO.  1997.  In vitro production of testosterone and plasma levels of luteinising hormone, testosterone and cortisol in male rats treated with heptachlor. E O Wango, D W Onyango, H Odongo, E Okindo, J Mugweru. Journal of the South African Veterinary Association. 73, 201-206. : Comparative biochemistry and physiology. Part C, Pharmacology, toxicology&endocrinology.118(3):381-6 Abstract
Male rats were divided into six groups of five rats each. Rats were injected subcutaneously with different concentrations of heptachlor for 2 weeks. Heptachlor at all doses significantly suppressed plasma testosterone levels (P < 0.05). Plasma luteinizing hormone (LH) (P < 0.01) and cortisol (P < 0.02) levels were significantly elevated in heptachlor-treated rats as compared to corn oil-treated controls. LH and testosterone levels showed strong correlation (r = 0.69, P < 0.05). The testes in rats treated with 25 mg/kg body weight of heptachlor showed some pathological changes. We conclude that heptachlor causes adverse effects on several male reproductive parameters in rats.

1995

MR. ODONGO, HESBONO.  1995.  In vivo and in vitro effects of graded doses of the pesticide heptachlor on female sex steroid hormone production in rats. Oduma JA, Wango EO, Oduor-Okelo D, Makawiti DW, Odongo H. Source Reproductive Biology Unit, University of Nairobi, Kenya.. Journal of the South African Veterinary Association. 73, 201-206. : Comp Biochem Physiol C Pharmacol Toxicol Endocrinolgy; 111(2):191-6 Abstract
Adult female Sprague-Dawley rats were injected with corn oil or 5 mg, 20 mg, 25 mg or 30 mg per kg body weight of heptachlor solution every other day for up to 18 days. The rats were killed at the end of the experimental period, and blood samples were assayed for progesterone and oestrogen by radioimmunoassay. Ovarian cells from the rats were isolated and incubated either on their own, or in the presence of LH or FSH, and production of progesterone and oestrogen determined. Control incubations consisted of cells from corn oil-treated rats. The latter were also incubated on their own or in the presence of LH or FSH. Heptachlor significantly suppressed blood progesterone and oestradiol levels (P < 0.05 to P < 0.001), the degree of suppression depending on the dose and the stage of the oestrous cycle in which samples were obtained. Production of oestradiol by ovarian cells from heptachlor-treated rats was lower than for corn oil-treated controls. Cells from rats treated with low doses of heptachlor (5 mg per kg body weight) showed an increased production of progesterone, while high doses (> 20 mg per kg body weight) suppressed production.

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