Structure parameter inference approach for endocrine feedback control SPINA is software for determining constant structure parameters of endocrine feedback control systems from hormone levels obtained in vivo. The first version of this cybernetic approach (SPINA Thyr, provided elsewhere) allows for evaluating the functional status of the thyroid gland, i.e. thyroid's secretory capacity (GT or SPINA-GT) and sum activity of peripheral deiodinases (GD or SPINA-GD). The software additionally provides means to calculate Jostel's TSH index (JTI) and the thyrotroph thyroid hormone sensitivity index (TTSI), two parameters for the assessment of the anterior pituitary function and the location of the set point of thyroid homeostasis. A second version (SPINA Carb, this repository) has been developed for insulin-glucose homeostasis. It delivers the secretory capacity of pancreatic beta cells (SPINA-GBeta), an estimate for the insulin receptor gain (SPINA-GR) and a static disposition index as a measure for the loop gain of the feedback loop (SPINA-DI). Both implementations of SPINA have been validated in clinical studies based on large cohorts.