Adipose Tissue's Potential Role as a Reproductive or Lactation Endocrine Gland

While adipose tissue secretes hormones related to nutrition and metabolism, a few studies have provided evidence suggesting a direct reproductive role from adipose-derived products. The goal of this study was to determine if adipose tissue serves as a reproductive or lactation endocrine gland. Adipose tissue was associated with the reproductive tract of mature female cows in two locations, mesosalpinx and mesometrium (tissues supporting the oviduct and uterus, respectively), in varying amounts. Using quantitative polymerase chain reaction on a non-descript pool of cows, LHβ, CGA, PRL, FST, and LEP transcripts were demonstrated to be present in mesosalpinx, subcutaneous, visceral, and peri-renal adipose depots. Subsequent efforts aimed to determine the influence of adiposity on transcript abundance. Body condition score was used to separate cows into two adiposity groups, which were confirmed by adipocyte size. Adiposity did not influence the abundance of LHβ, but the CGA transcript was influenced by the adiposity by depot interaction. The PRL transcript was also not influenced by adiposity. The FST transcript was more abundant in BCS 3 cows, while LEP was more abundant in BCS 6 cows. Protein efforts utilizing an RIA revealed the presence of luteinizing hormone in all four adipose depots. Using an antibody against purified pituitary-derived prolactin, a band was detected in 6/9 mesosalpinx adipose depots similar in size to that observed in the pituitary. Presence of transcripts and hormones in adipose tissue provides the framework necessary for adipose to be a reproductive or lactation endocrine gland, though secretion would also be required. Secretion of such hormones by specific adipose depots could provide local effects to nearby tissues.