The acute leptin response to GH

The effect of an acute bolus of GH on serum leptin in normal individuals and the factors affecting this response have not previously been studied. Seventeen healthy volunteers with normal body mass index, with ages ranging from 20.5–78.2 yr were studied. Each subject received three single doses of GH in random order at least 4 wk apart. Bioimpedence analysis was performed to provide estimates of fat and lean masses. Serum samples for leptin, insulin, and IGF-I were taken 0, 18, 24, 48, 72, and 120 h after each dose of GH. Leptin levels changed significantly after the 0.67- and 7-mg doses of GH, but not after the 0.27-mg dose. Compared with baseline, there was a significant elevation (P &amp;lt; 0.001) in serum leptin levels at 24 h, followed by a significant decrease (P &amp;lt; 0.01) at 72 h. Baseline and peak leptin levels were significantly determined by gender, fat mass, and log10 insulin. Nadir leptin levels were significantly determined by gender and fat mass. In contrast, the increment in leptin levels was significantly determined by age, although this only accounted for 24% of the variability in the increment in leptin levels. We have demonstrated that administration of a single bolus dose of GH significantly increases serum leptin levels, followed by a significant nadir. This occurs not only after a supraphysiological dose of GH, but also after 0.67 mg, a dose within the physiological replacement range. The increment in leptin increases with advancing age, suggesting that at the level of the adipocyte, aging increases responsiveness to GH. However, this only partially explains the changes seen, and it is likely that another factor(s) is involved in the acute impact of GH on circulating leptin levels. The presence of a significant nadir after the peak in leptin levels supports the existence of a negative feedback loop, linking circulating leptin to its own biosynthesis in adipose tissue, mediated by peripheral leptin receptors. These data provide unequivocal evidence that GH can affect serum leptin levels in the absence of a change in body composition.</jats:p

Interactions between GH, IGF-I, Glucocorticoids, and Thyroid Hormones during Skeletal Growth

Readers of Harriette Simpson Arnow’s most well-loved novel The Dollmaker had to wait sixteen years for her next work, The Weedkiller’s Daughter (1970). Clearly, the book was no quick cash-in. By the time Arnow was in her fourth decade of writing, the literary landscape had changed radically. The reviews for The Weedkiller’s Daughter reflect this shift. While many reviews of this contemporary account of a daydreaming teenage girl’s life in suburban Michigan praised Arnow’s sensitivity in portraying adolescents, a vocal minority took Arnow to task for the book’s anachronisms in post-Woodstock America. One review attacked the main character for being a “dull little frump.” Another snidely recommended the novel to “a few middle-aged virgins in Nebraska.” It would be grossly misstating the facts to claim that the mixed reception of The Weedkiller’s Daughter alone drove Arnow to write history and historical fiction subsequently. But one cannot ignore the fact that Arnow shunned the writing of contemporary fiction after 1970. Arguably, her choice to compartmentalize her rural Kentucky past from her suburban Michigan present cost her readers. This paper presentation is based on my own work with the Arnow Collection at the University of Kentucky’s Special Collections, both as an assistant archivist and as a researcher-scholar. I conclude from studying manuscripts and reviews of the novel that Arnow was unfairly pigeonholed as a regionalist writer, charged with writing barely fictionalized social commentary, when The Weedkiller’s Daughter was created as a reimagining, rather than a recapitulation, of themes found in The Dollmaker