The influence of ovine follicle stimulating hormone (FSH) and luteinizing hormone (LH) on the male reproductive system and the skin of the mediterranean Blenniid fish Blennius sphinx (valenciennes)

Publisher Website
Google Scholar
Abstract
The Mediterranean Blenniid fish Blennius sphinx has a unique male reproductive system: the testes lie close to voluminous lipid bodies through which the sperm must pass. The tubules, through which the sperm travel, lead to a collection duct opening ventrally into locally enlarged sperm ducts. These taper off caudally and join in an unpaired terminal section which opens into a genital papilla. Slightly posterior to the union, the duct forms two blind pouches extending laterally to the caudal third of the testes. In addition, during spawning, Blennius sphinx shows a glandular system of unknown function in the first and second spines of the anal fin.In this paper, the reactions of the sex‐linked structures described above, and of the mucous cells in the epidermis of post‐spawning fishes, to injections of mammalian FSH and LH are studied. By LH‐treatment the proportion of the animals with fully active testes is increased from 36% (controls) to 83%. The height of the lipid body is increased about 26% by LH‐injections, as compared with the controls. This effect is correlated with an increase in the size of the lipid vacuoles of about 28%. In the epithelium of the paired portions of the sperm duct, LH promotes the formation of aldehyde fuchsin‐positive granules in the cells. The proportion of this type of secretion rises from 18% (controls) to 68% after LH‐treatment. In the terminal unpaired part of the sperm duct, within the genital papilla, the epithelium is thickened by about 38% by this hormone. Injections of LH decrease the height of the blind pouch epithelium, which is well developed, and actively secreting in most of the controls. They also suppress secretion and vascularisation in this structure. LH promotes the formation of the anal gland system, increasing the proportion of the animals with maximally developed glandular systems from 0% (untreated controls) or about 17% (H2O‐treated controls) to 91%. This effect is correlated with an increase of the diameter of the single glands of about 40%. This is also the case in FSH‐treated fishes (23%). The number of the mucous cells in the epidermis decreases by 46% and 45% after FSH‐ and LH‐treatment, respectively. In no case were the effects strictly correlated with the hormone dose. The problems of the action of mammalian gonadotrophins, especially FSH, in fishes; the possible functions of the organs associated with the male genital tract of Bl. Sphinx, and the possible role of the mucous cells in the osmoregulation of fishes are discussed.