Life Lines by Dr. Dolittle

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Leptin influences mammalian bone development

Leptin is a hormone that was discovered in 1994 and was once heavily studied by researchers who had hoped it might be useful in promoting weight loss.  It is produced by fat cells and signals to the brain whether those fat cells have sufficient energy, at which time it suppresses hunger and thereby promotes weight loss (WebMD; Klok et al., 2007). One of the reasons it failed as a weight loss supplement is that people who are obese are resistant to the effects of leptin.
While excitement over leptin as a cure for obesity has faded, excitement over discovery of its other roles in the body continues (Crespi et al., 2006). For example, a study of South African clawed frogs (Xenopus laevis) showed that, although similarity between the clawed frog and mammalian leptin is rather low (only 35%), it produces a similar appetite suppressant effect in the frogs (Crespi and Denver, 2006). What I found more interesting in this early research was the discovery that leptin helped regulate hindlimb growth and development of the frogs (Crespi and Denver, 2006).
800px-Sheep,_Stodmarsh_6

Photo by Keven Law, Los Angeles, USA [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)%5D, via Wikimedia Commons

Now, a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology shows that leptin is found in bone and cartilage of developing sheep as well. In fact, De Blasio et al., used microcomputed tomography to show that leptin plays a role in the growth and development of bones in fetal sheep.
Sources:

WebMD

Klok MD, Jakobsdottir S, Drent ML. The role of leptin and ghrelin in the regulation of food intake and body weight in humans: A Review. Obesity Reviews. 8(1): 21-34, 2007.

Crespi EJ, Denver RJ. Leptin (ob gene) of the South African clawed frog Xenopus laevis. Proc Natl Acad Sci USA. 103(26): 10092-10097, 2006.

De Blasio MJ, Lanham SA, Blache D, Oreffo ROC, Fowden AL, Forhead AJ. Sex- and bone-specific responses in bone structure to exogenous leptin and leptin receptor antagonism in the ovine fetus. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology.  https://doi.org/10.1152/ajpregu.00351.2017

Categories: Comparative Physiology

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