Dw Onyango

Khat (Catha edulis) lowers plasma luteinizing hormone (LH) and testosterone secretion, but increases cortisol levels in male rabbits

AIM 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.

Morphological characterization of the seminiferous cycle in the goat (Capra hircus): A histological and ultrastructural study

The cycle of spermatogenesis/seminiferous cycle was investigated in the goat testis using both light and electron microscopy techniques. Using the various cell associations and the accompanying changes in spermatid shape and location, the cycle was divided into eight (8) successive stages. The cycle began with the accomplishment of spermiation (stage 1) and ended with apical migration and close attachment of late maturation phase spermatids at the Sertoli cell apex accompanied by adluminal retention of residual bodies with dense staining inclusions (stage 8). The early stages of the cycle (stages 1-4) were therefore characterized by the presence of only one generation of spermatids, the second one appearing only after the division of secondary spermatocytes in stage 4. Consequently, stages 5-8 had two generations of spermatids; Golgi or cap phase as well as maturation phase spermatids. Although stages 5 to 7 appeared as distinct entities, stages 6 and 7 were rather short-lived and considered as continuations of stage 5. Therefore, the 8 stages of the cycle in the goat were further condensed into 6 main divisions. The duration of each stage was estimated by the frequency of occurrence in sections. Among these, stage 1 had the highest frequency (34%) followed by stages 5-7 (27%). Stages 8 and 4 had the shortest frequency (up to 9%) while stages 2 and 3 had 13% and 12% respectively. These results indicate that, like most domestic species, goats have a cycle of 8 stages with 6 main divisions, the longest being stage 1.

In Vitro Production of Testosterone and Plasma Levels of Luteinising Hormone, Testosterone and Cortisol in Male Rats Treated with Heptachlor

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.

Ultrastructural study of the testis of non-breeding naked mole-rat (Heterocephalus glaber, Ruppell)

The testicular structure of the wild caught naked mole rat was studied. It comprises of a large volume of lipid-rich interstitial cells of Leydig among which are few scattered seminiferous tubules. In addition, the interstitial cells possess elongated mitochondria and vast network of smooth endoplasmic reticulum (sER). The Golgi apparatus (GA) apparently is not conspicuous or well developed. All stages of spermatogenesis occur in the seminiferous tubules although the mature forms (secondary spermatocytes, spermatids and spermatozoa) are few. Sertoli cells show an irregular nucleus, mitochondria oriented perpendicular to the basement membrane, a vast network of endoplasmic reticulum with sER as the predominant form and lipid droplets. The ultrastructural features of Leydig cells seem to suggest a steroidogenic capacity although the vast accumulation of lipid droplets may imply impaired utilisation of cholesterol reservoir as a result of pituitary hormonal imbalance or (and) the local paracrine influence by Sertoli cells. The cause of slow-down in spermatogenesis is still unclear but may also be under the influence of pheromonal cues or the local paracrine control. Sertoli cell features point towards a role of synthesis and secretion.

High khat dose and long-term exposure impairs spermatogenesis: experimental study using rabbit model

Introduction: This study investigated shortand long-term effects of khat (Catha edulis) on hypophyseal, epididymal and testicular morphology, body weight and temperature changes and haematological parameters of rabbits. Materials and Methods: Twenty five male New Zealand White rabbits, divided into five groups were used. First four groups were administered, via intra-gastric tube, 1.5, 4.5, 13.5 and 40.5 g/kg body weight respectively of khat extract thrice a week for 8 weeks while controls received normal saline. Short-term and long-term effects were evaluated for hypophyseal, epididymal and testicular morphology, body temperature as well as body weight changes, food consumption and haematological parameters. Data on haematological parameters, body weight changes, body temperature and food consumption was done using one-way ANOVA at 95% confidence interval using SPSS version 12.0. Results: There was vacuolation in spermatogonia and spermatocytes at high doses while epididymides and hypophyses were unaffected. A significant decrease (P<0.05) in body weight of treatment groups correlated with reduced food intake with increasing doses and chronicity of exposure. Packed cell volume, red blood cell count and haemoglobin concentration decreased while white blood cell count increased with increasing doses. Conclusion: Khat extract had direct effects on spermatogenesis compounded by poor body weight gain, hyperthermia and blood volume loss.

The Functional Morphology and Adaptations of the Epididymis in a Testicndid Mammal, The Rufous Sengi (Elephantulus rufescens).

Sengis are testicondid African mammals that constitute Order Macroscelidae. The epididymal morphology in the rufous sengis ( Elephantulus rufescens ) was studied with focus on features and adaptations that make it suitable for sperm maturation and storage in this testicondid mammal. The three topographic regions were distinct with the caput and cauda epididymis placed far apart, connected by a slender corpus. The caput occurred as a longitudinal mass on the dorsolateral border of the testis while the Cauda, pear-shaped mass, was laterally placed between the rectum and the pelvic urethra. The epididymal epithelium comprised principal and basal cells; the former exhibiting granules and apical blebbing in the caput. The lumen of the cauda was densely packed with spermatozoa that are occasionally wrapped by amorphous dark masses, and its principal cells had numerous vacuoles. This study demonstrates that beside merocrine secretion, principal cells of sengi’s caput also exhibit apocrine secretion as shown by apical blebs. The blebs are shed off plausibly as a means of delivering epididymosomes to the lumen, which in turn transfer epididymis-secreted proteins to the spermatozoa. Additionally, the study has shown that the cauda epididymis descends to a site probably cooler than the core body temperature for optimal sperm storage, with the vacuoles indicating its involvement in fluid re-absorption and phagocytosis.

Frequency of stages of the seminiferous cycle in the thick-tailed bush baby (Otolemur garnetti ), a prosimian primate: possible phylogenetic implications?

Spermatogenesis in the thick-tailed bush baby, Otolemur garnetti, was studied using light microscopy. The stages and stage frequencies of the cycle of the seminiferous epithelium were determined using semithin sections stained with methylene blue-azure II. These sections were obtained from the testes of six healthy adult males (n=6). They revealed 11 stages of the seminiferous epithelial cycle in this species. The mean relative frequencies of the stages I–XI were 10.9, 6.0, 5.9, 7.3, 13.2, 10.7, 11.7, 9.2, 7.6, 8.9 and 8.6, respectively. Comparisons were made between the frequency data in the thick-tailed bush baby and equivalent data in the rat, hamster, macaque, baboon, chimpanzee and man. There was a significant correlation (P<0.05) between the Otolemur data and equivalent stage frequency data of two rodent species (rat and hamster) and monkey (Macaca arctoides). However, there was no significant correlation between the present data and those of the baboon, chimpanzee and man. Possible phylogenetic implications of these findings are discussed.