PLASMA-LEVELS OF GH AND PRL AND CONCENTRATIONS IN THE FLUIDS OF BOVINE OVARIAN CYSTS AND FOLLICLES

Prolactin and GH have been detected within the ovary, and it has becom e increasingly evident that they have a role as intrafollicular regula tory Factors. The aim of the present work was to gain an insight into the elements influencing intraovarian GH and PRL in bovine species and to see whether cystic degeneration was accompanied by abnormal bovine GH (bGH) and PRL (bPRL) plasma patterns. We followed the relationship s between plasma and ovarian fluid bGH and bPRL concentrations over an entire year in Friesian cows whose ovaries showed distinct types of s tructures. To assess the presence of bGH and bPRL within ovarian cells , we assayed selected ovarian structures by immunohistochemistry. The results demonstrated that: 1) plasma and ovarian fluid hormonal concen trations were independent, and their ratio was independent of the ovar ian structure classes, subclasses and period of the year; 2) in the ma jority of the cows the concentration of bGH in ovarian fluid was no mo re than 80% of the level in plasma, whereas in about half the animals bPRL concentrations were higher in the ovary than in peripheral plasma ; 3) mean bPRL concentrations in ovarian fluids were significantly hig her in summer than in winter; 4) immunoreactive bGH and bPRL were pres ent within granulosa and luteal cells. Thus, it is suggested that in t he cow bGH and bPRL levels in the ovary might be regulated in some way independently of the pituitary. (C) 1998 by Elsevier Science Inc.