Endocrine Abstracts

The IGFs are present ubiquitously at very high levels throughout the body and affect virtually every aspect of cell function. These high levels are maintained due to their association with 6 distinct binding proteins (IGFBP-1 to -6) which specifically bind IGFs (but not insulin). The IGFs are not stored within any cells but are stored in the circulation due to their binding to IGFBP-3 which then results in its association with a large glycoprotein, the acid labile subunit (ALS...

IGFs act as amplifiers of gonadotrophin (Gn) action in the ovary, but their activity is modulated by IGFBPs. In addition, we have shown IGF-independent inhibitory effects of IGFBP-4 on ovarian steroidogenesis. The aim of this study was to investigate the possible mechanism of action of IGFBP-4 in ovarian cells.Granulosa cells (GC) and theca were harvested from intact follicles (2.5-14mm) dissected from 8 pairs of ovaries collected with ethics committee a...

The role of prolactin in the regulation of ovarian folliculogenesis and in particular it's relationship to follicular atresia is as yet unclear; although a decline in prolactin concentrations in bovine follicular fluid appears to be related to morphological signs of atresia. In addition to the pituitary and endometrium sources of prolactin, there is also a local ovarian source of prolactin. Hence a potential autocrine mechanism of prolactin action may exist in the ovary. We in...

The IGF/IGFBPs are important in follicle growth and selection, with IGFBP-4 being one of the major players in this system. We have shown potent, IGF-independent, inhibitory effects of IGFBP-4 on steroidogenesis, explaining its' preferential proteolysis in healthy follicles. Two isoforms of IGFBP-4 exist, non-glycosylated and glycosylated, at approximately 24 and 28kDa, with different susceptibility to proteolysis. We therefore investigated the production of IGFBP-4 isoforms by...

IGFs and IGFBPs have an important role in folliculogenesis, with the profile of IGFBPs being different in healthy and atretic follicles. In particular, IGFBP-4, which is a potent inhibitor of steroidogenesis, is preferentially proteolysed in healthy follicles. We therefore investigated the production and activation of IGFBP-4 protease in human follicular cells.Follicles of 3-25mm were dissected from 13 pairs of ovaries collected with ethics committee app...

Childhood obesity is increasing in prevalence and is associated with insulin resistance and Type II diabetes in later life. Site-specific differences in adipose tissue accumulation and associated insulin sensitivity may contribute to these problems.The aims of our study were: 1. To isolate and characterise, subcutaneous (SC) and visceral (V) preadipocytes using small biopsies from pre-pubertal children (ages:4-8years(n=3)) undergoing elective abdominal surgery, with normal...