Insulin-like and fibroblast growth factors and their receptors are differentially expressed in the oviducts of the common marmoset monkey (Callithrix jacchus) during the ovulatory cycle.

Abstract

It is suggested that growth factors support the process of maturation and differentiation in the mammalian oviduct. Fibroblast growth factors (FGF) and insulin-like growth factors (IGF) are possible influences on these processes. The present study describes for the first time the expression of FGF-1 and -2 and their receptors as well as IGF-1 and -2 and the corresponding IGF receptor type 1 in the oviduct of the New World monkey Callithrix jacchus. Because of the limited RNA yields from oviducts, reverse transcription-polymerase chain reaction (RT-PCR) was performed to estimate expression levels. Expression patterns were found to be similar for all examined growth factors and receptors: the highest mRNA contents were obtained at the late proliferative and early to midsecretory phases, compared with lower levels during the early proliferative phase. Elevated amounts of these RNAs were correlated with high serum estradiol but not with progesterone concentrations. Each PCR product showed a high degree of homology (> 92%) to the known human sequences. Immunohistochemical analysis indicated greater specific staining for FGF-1 and -2 and IGF-1 before ovulation on the luminal epithelial surface of marmoset oviducts in comparison to the other cycle phases. Differences in staining intensity were not observed between the ampulla and isthmus. In summary, the marmoset oviduct expresses all components of functional FGF and IGF systems, thus suggesting auto-/paracrine effects of these growth factors within the primate oviduct, possibly under the control of estrogenic hormones.